Digital to analog converters (DAC) are widely used in disc drive read channels which require ever greater resolution to meet the increasing demands of data processing. However, increasing the resolution of a DAC introduces certain problems. For example, current source DACs generally double in size for each additional bit added. An alternate form of DAC, the R2R ladder DAC, grows linearly, i.e., it simply adds one more R and one or more 2R resistor pairs for each additional bit of resolution. However, these devices do not have the required precision because the MOS resistors used in the ladder cannot typically be made with the required precision.